Is it possible for a DataCooker to use the built-in ETW pipeline as source?

I'm looking into writing a plugin which takes generic ETW events and uses them to populate a custom table.
It looks like this should be possible by defining a DataCooker which uses one of the DataCookers that WPA ships with as its source. But which one? Are these documented somewhere? Is this intended to be possible, or should plugins load their own data from scratch and effectively reimplement the entire ETW pipeline?

Some background for what I really want to achieve: I have an application which emits custom ETW events, and I can visualize these in WPA's Generic Events table, but I'd like to be able to visualize them as spans with a begin/end time. As far as I can tell this cannot be configured in WPA on an existing view, so I would instead have to write a plugin which takes the ETW data, cooks it and feeds it into a custom table definition, assigning appropriate roles to the individual columns. But to do that, I would either need to write the entire pipeline, loading the .etl file and parsing myself, or I would need to use one of the standard DataCookers to use as my source, and for that I need to know the DataCooker path and type.

How would I achieve any of this? If I'm way off and a completely different approach should be used, any pointers would be welcome too. :)

The issue names DataCooker, WPA's Generic Events table, ETW, and .etl files but no repository files or tests. Start by locating the built-in DataCooker definitions and plugin documentation; done would be a documented supported path or a clear alternative for turning generic ETW events into spans.